1. Technical Field
This invention relates generally to parachutes, and more particularly to a circular parachute.
2. Description of Related Art
A typical circular parachute includes a canopy to which a set of suspension lines is attached. The suspension lines connect the canopy to a harness that attaches to a person, cargo, or other load. Air inflates the canopy during descent and the drag provided reduces speed.
The canopy of a circular parachute (i.e., a round parachute) is commonly made of a circularly shaped nylon fabric (i.e., the canopy fabric). The canopy of the flat circular type has an outer perimeter that forms a circular configuration when the canopy is laid flat upon the ground. When fully inflated, the canopy usually takes the shape of a hemispherical cap, although in some cases, the cap is slightly conical and in others, slots or concentric gaps are provided in the canopy that enhance stability. A circularly shaped central opening is often provided in the canopy to form a vent at the apex of the canopy. The circularly shaped marginal edge portion of the canopy along the perimeter of the vent is sometimes referred to as the “vent band” of the canopy, while the circularly shaped marginal edge portion of the canopy along the outer perimeter is sometimes referred to as the “skirt band.”
Suspension lines nowadays are commonly nylon too, although some use materials available under the trademarks KEVLAR and SPECTRA. They function to suspend the load from the canopy. For canopies having a vent, vent suspension lines are attached to the vent band. With the canopy descending vertically and fully inflated, the vent suspension lines converge downwardly in a vent suspension line confluence extending to a single, vertically extending, vent centerline. Main suspension lines are attached to the skirt band. With the canopy descending vertically and fully inflated, the main suspension lines converge downwardly in a main suspension line confluence extending with the vent centerline to a suspension line junction that is connected to a harness for the load.
One recognized problem common to the canopy and the suspension lines appears as the parachute is deployed. The suspension lines unfold until they are fully stretched. Then, the canopy unfurls and begins inflating. As that occurs, sudden shocks and other large forces are produced that can cause random failures modes, including structural failures of the canopy and/or suspensions lines. Various techniques exist to help overcome this problem, but improvement remains desirable. Thus, a need exists for a better circular parachute configuration.